From TUAW:

ERIC WOEHLER If you get the message that "No version of the software found on volume", due to having removed all the megabytes of language files etc, you can still get the installer to run.

1. Download the update from MS and save the updater on yr desktop - you will be modifying the file, so need to be able to edit and save it
2. Right click on the Updater and click "Show Package Contents".
3. Navigate to Contents -> Resources. You need to modify the script: package_updatable.
4. Remove these lines using Text Edit or BBEdit or similar:

if not found_valid_version:

sys.exit(48)

Save these changes to the Updater then close. Now it will update.

I had to open the .DMG and copy the file onto my HDD before I could show contents. Installed perfectly though. Enjoy